It's always interesting to think about if some of the biggest performances in movie history were played by different actors. There are so many iconic performances out there that it is genuinely difficult to imagine any other actor in the role that they have become so famous for. Little do we know is that there are countless instances where these actors almost didn't snag their famous parts in these iconic movies. It happens more times that you'd think in Hollywood. After all, the casting process is a long and gruelling process that can take months before a studio finds the perfect actor for the part. And even then, it's never a given that said actor is the one who find themselves in the finished product of the film. They might leave the set at the last minute and get replaced by some other actor. There are several instances where stuff like this happens in Hollywood, and we are going to go over a few of them in this list below.

15 Al Pacino — The Godfather

The road to playing Michael Corleone was a difficult one for Al Pacino. At the time of auditioning, Pacino worked heavily in the theater world, but only had one other film under his belt. Therefore, despite the director loving him and wanting to immediately cast him, the studio wanted a bigger name to star in The Godfather. Several big-name actors went on to audition for the part, including James Caan, who went on to play Michael's brother Sonny. Other actors like Martin Sheen auditioned, but none of their performances could compare to Pacino. The studio offered the part to Robert Redford, but he declined. Eventually, the studio begrudgingly cast Al Pacino.

14 Johnny Depp — Pirates Of The Caribbean

The character of Captain Jack Sparrow is arguably the most iconic role in Johnny Depp's career, but it almost went to someone else entirely. There were actually quite a few actors that were in the running. The biggest being Jim Carrey, who was actually offered the part, but declined due to his schedule which conflicted with Bruce Almighty. Other actors who were considered were Christopher Walken, Rik Mayall, and Michael Keaton. Robert De Niro was offered the part, but declined. Hugh Jackman was briefly considered in his pre-Wolverine days, but the studio figured he wasn't a big enough star. Matthew McConaughey was actually the physical inspiration behind the character, but the studio wasn't actually able to cast him.

13 Bill Skarsgård — IT

Bill Skarsgård has been praised for giving a splendidly terrifying performance as Pennywise in the latest It adaptation, but originally, Will Poulter was cast in the role. The star of Detroit and We're the Millers was cast back when the film's original director, Cary Fukunaga, was still at the helm. After Fukunaga left production and was replaced by Andres Muschietti, the two started working closely together in the planning process, but as time went on, Poulter felt himself to be "disengaged" from the role after realizing just how terrifying and dark it was. Fun fact: Before Skarsgård was cast, the studio hoped to bring in a gender-bent Pennywise played by Tilda Swinton, but she was too busy.

12 Arnold Schwarzenegger — The Terminator

The title role of The Terminator was the part that would both define and launch Arnold Schwarzenegger's career as an action star. Shockingly enough, he was never the original choice for the part. The only thing more shocking than that is knowing who the studio originally wanted for the part — O.J. Simpson. When the director James Cameron was told by a studio exec who they wanted to cast, he was flabbergasted. Not only did he struggle to imagine Simpson as a killer, he didn't like the kind of implication/imagery that a "black athlete chasing this white girl around Los Angeles with a knife and a gun" would invoke. Years later, O.J. Simpson was on the stands for allegedly killing Nicole Brown Simpson.

11 Michael J. Fox — Back To The Future

While most of the entries on this list mention actors who were replaced before filming had commenced, Back to the Future was well into production when Eric Stoltz was in the role of Marty McFly. Unfortunately for Stoltz, the director realized after a few weeks of filming that Stoltz was far too serious for the part. Director Robert Zemeckis wanted his lead to inject a certain level of wit and humor into his performance to fit the film's comedic tone, but Stoltz played the role far too straight. After that, they fired Stoltz and replaced him with Michael J. Fox, who the studio wanted all along. When they were originally casting for the part, Fox was preoccupied with his show Family Ties, but when his schedule reopened just as Stoltz left, he was all onboard.

10 Michelle Pfeiffer — Batman Returns

Out of all of the actors who have played Catwoman on both the big and small screen over the years, Michele Pfeiffer portrayal of the character from Batman Returns is the definitive Catwoman for many fans. She almost never donned the suit to begin with, and at the start of production was not even the original actress who was cast in the role. At first, Annette Bening was cast as Catwoman. Before they started filming, Bening had to drop out of the part after discovering she was pregnant, which meant she obviously couldn't pull off any of the character's stunts. The role was brought to Pfeiffer who wanted the role long before Bening was cast.

9 Chris Pratt — Guardians Of The Galaxy

After getting insanely ripped for the part of Peter Quill in Guardians of the Galaxy, the formerly portly star of Parks and Recreation, Chris Pratt, became an instant Hollywood superstar overnight. However, had Pratt not gotten the part, the studio had some very different plans for the character. Interestingly enough, they wanted him to be played by comedian Glenn Howerton. That name may not ring any bells immediately, but he sure does have a recognizable face to fans of It's Always Sunny in Philadelphia; he plays Dennis on the show. Howerton auditioned right after Pratt and had director James Gunn not cast Pratt, he would've been keen on working with Howerton.

8 Scarlett Johansson — Iron Man 2

For several films in the Marvel Cinematic Universe, Scarlett Johansson has been a staple of the franchise as Black Widow, with recent reports suggesting Marvel is planning to finally give her a solo film. Prior to being cast in the part, several other actresses were in the running to play Black Widow but for one reason or another, didn't get it. Some of which included Angelina Jolie, Jessica Biel, Natalie Portman (who wound up getting a very different role in the MCU years later), and Jessica Alba. Emily Blunt was actually Marvel's very first choice to play Black Widow, but she turned it down. Gemma Arterton was considered after Blunt dropped out, but it didn't work out.

7 Ryan Gosling And Emma Stone — La La Land

Apart from the Best Picture fiasco which closed out the Oscars last year, La La Land is best remembered for giving Ryan Gosling a Best Actor nomination and Emma Stone a Best Actress win. Originally, this was not the pair which were planned to act side by side in the film. Originally, as far back as 2014, Emma Watson and Miles Teller were prepping to hop and bop in the musical hit. Watson left because she realized wouldn't have the time to do both La La Land and Beauty and the Beast, so she picked the latter. With Teller, it's more complicated. According to Teller, he received a call that the director no longer thought Teller was "creatively right" for the project. Other sources claim that Teller held out to be paid more money and the studio decided it would be less costly to just fire him.

6 Jennifer Lawrence — Silver Linings Playbook

The lead role of Tiffany in Silver Linings Playbook was the part that solidified Jennifer Lawrence as a mainstay in Hollywood, as it was the first role to win her an Oscar. Originally, Anne Hathaway was cast in the role and was actually the studio's first choice, but due to creative differences with director David O. Russell, Hathaway wound up walking away from the production altogether. It's also worth noting that Mark Wahlberg was originally cast in the part that eventually went to Bradley Cooper. For unknown reasons, Wahlberg left production. Had he and Hathaway stayed, they would have been co-stars.

5 Matt Damon — The Bourne Identity

When The Bourne Legacy was released with Jeremy Renner as the star, fans of the franchise were outraged because they believed that no one except Matt Damon should be starring in these movies. The funny thing about that is that Matt Damon was close to not being the star of any of these Bourne movies. When the studio was looking for someone to star in The Bourne Identity, they couldn't get passed seeing the scrawny kid from Good Will Hunting whenever they looked at Damon. He was a far cry from the action star they had in mind, so they asked Brad Pitt, Russell Crowe, and Sylvester Stallone to play the part. They all turned it down and the part miraculously fell into Damon's lap.

4 Audrey Hepburn — Breakfast At Tiffany's

Audrey Hepburn is one of the most celebrated actresses of hers or any generation. Undoubtedly, her most memorable performance was the Oscar-nominated lead role in Breakfast at Tiffany's. It was revealed a few years ago in a documentary called Crazy About Tiffany's that not only was Hepburn not the first choice for the part, but Marilyn Monroe was. Truman Capote, the author of the original book and friend to Monroe, had actually written the character with Monroe in mind. However, when auditions came to pass, it was Hepburn who won the part, which Capote was not happy about.

3 Alfonso Ribeiro — Fresh Prince Of Bel Air

One of the most iconic characters in television history happens to be Carlton Banks from TheFresh Prince of Bel Air. Much of that has to do with his dance and the hysterical performance that Alfonso Ribeiro put in every week. Oddly enough, the network were not as fond of Ribeiro's performance initially. After he was cast in the role and filmed the pilot, the president of NBC wanted someone else cast in the role. When they could not find anybody else to fill the character's shoes, Ribeiro was brought back in. So all in a short amount of time, Ribeiro was hired, fired, and then rehired.

2 Kerry Washington — Scandal

In many ways, Scandal was a breakout role for its star Kerry Washington, but the role was almost not hers to begin with. Originally, ABC wanted Connie Britton to play Olivia Pope while she was still fresh off the success of Friday Night Lights. When the show's creator Shonda Rhimes was told by an ABC exec that Britton would be perfect for the part, Rhimes emphasized that the character was African American and she would not settle for anything less than a black woman for the role. After that was settled, several black actresses were brought in to test for the part. Among them being Anika Noni Rose, Jill Scott, and Kerry Washington. Washington was who won the network over.

1 Andrew Lincoln — The Walking Dead

Andrew Lincoln has been so closely associated to the role of Rick Grimes on The Walking Dead that it is difficult to imagine anyone else filling the sheriff's shoes. Interestingly enough, he was never supposed to play the part to begin with. Back when Frank Darabont was still onboard of the show in the early stages of production, he had every intention of casting Thomas Jane in the role after the two enjoyed working with one another on the set of the Stephen King adaptation, The Mist. Sadly, Jane had to pass due to commitments as star of the HBO series Hung. And so the audition process for the part of Rick Grimes commenced, and as we all know, Andrew Lincoln snagged it.